#include <cstdio>

const char FIN[] = "tije.in";
const char FOU[] = "tije.out";

int i, j, k , N;

int main()
{
    freopen(FIN,"r",stdin);
    freopen(FOU,"w",stdout);

    scanf("%d",&N);

    for (i = N; i > 1; --i)
        printf("%d %d\n", i , N + 1);
    for (i = 1; i <= N; ++i)
    {
        for (j = N; j > i; --j)
            printf("%d %d\n", i , j);

        for (j = 1; j < N; ++j)
            printf("%d %d\n", N + 1 , i);

        for (j = N; j > i; --j)
        {
            for (k = 1; k <= i; k++)
                printf("%d %d\n", j , j + 1);
            if (j - 1 != i)
                printf("%d %d\n", j , N + 1);
        }
    }
    return 0;
}